In many hard rock mining operations it is common practice to employ large flow rates of ventilating air to dilute and remove undesirable or dangerous gases such as carbon oxides and methane. Air flow can be directed and controlled by hanging heavy cloth, e.g. vinyl-coated, fabric known as brattice cloth, throughout a mine. For instance, light weight, plastic-coated, brattice cloth is hung against tunnel surfaces, e.g. ceilings and walls, to reduce frictional air drag. And, heavier weight, plastic-coated brattice cloth is hung across tunnel openings to divert air flow away from certain tunnels or rooms. Such brattice cloth must be flexible, durable and tear-resistant to withstand repeated impact from pedestrian and vehicular traffic passing through an area blocked by a brattice cloth.
One version of brattice cloth comprises vinyl sheets laminated to an open web reinforcement fabric. The reinforcement fabric adds tear strength and toughness to the cloth. In coal mining operations it is desirable to use a flame-resistant, brattice cloth, i.e. a brattice cloth meeting industry or government standards for fire-resistance. High loading of fire-retardant fillers are commonly used to render such plastic-coated, cloth laminates fire-resistant. Such fillers however will make a plastic sheet opaque which creates hazards to people and equipment which may be located in the area behind a brattice cloth. For instance, such people and equipment are susceptible to impact from vehicles passing through a brattice cloth screen. Thus, to avoid such collisions it is desirable to use non-filler fire retardants to provide transparent cloth which allows perception of people and objects behind a transparent cloth.
Transparent cloth, however, does not always permit a determination of what is immediately behind the brattice cloth, for instance, a mine wall behind a wall covering brattice cloth and a dimly lit tunnel behind a brattice cloth tunnel curtain. Thus, transparent brattice cloth leaves open the possibility that a vehicle driver who is intending to pass through a tunnel blocking brattice cloth may accidentally collide with a brattice cloth-lined, tunnel wall. Thus, it would be desirable to employ a reflective device on such transparent, brattice cloth but for the fact that most useful retroreflective devices that could be used in brattice cloth are so highly flammable as top offset the benefits of fire retardants used to reduce the flammability of plastic coatings.